<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		<script>
			var b=0;
			var c=0;
			var a="dfjd5555ffdfeww555wf";
			for(var i=0;i<20;i++){
				if(isNaN(a[i])==true){
					c+=1;
				}else{
					b+=1;
				}
				
			}
			document.write("字母个数:"+c+"数字个数:"+b);
		</script>
	</body>
</html>
